ive heard of a couple people having problems with their dinan chips after about a year or two, and L337E46 on this site had problems with his JC shark injector when he tried to restore the default settings. so i would say there's always a small amount of risk involved in getting a chip, but they are made to be totally compatible with your engine and the new settings shouldnt effect the reliability, its just the tampering with the ecu that could cause problems.